The current line of FitBit personal activity trackers includes four wrist-worn models: the FitBit Flex, FitBit Charge, FitBit Charge HR, and the FitBit Surge. Although each of them serve a similar purpose, tracking the daily exercise and activity habits of the wearer, they all present a different set of features and options that may make one model more suitable for a given user.

FitBit Charge

The FitBit Charge is the least expensive of the wristborne FitBit models, commonly retailing for less than any of its line-mates. Like all FitBit trackers, it has an internal accelerometer that measures motion patterns to determine activity levels as well as sleep quality, but its lower price point comes at the expense of some of the more premium features.

FitBit Charge HR

A direct upgrade from the FitBit Charge, the Charge HR adds heart-rate monitoring functionality to the activity tracking capabilities of the base model. It also has a watch-buckle strap that provides a more secure fit. The Charge HR also includes a vibration monitor that works with the scheduling app of a smartphone to vibrate when an alarm is set to go off as well as an altimeter that measures stairs and other inclines climbed.

FitBit Flex

The FitBit Flex is a minimalistic take on the personal activity tracker, featuring a system of flashing LEDs in place of a more developed display. Each one of the lights represents 20 percent of your daily goal, and tapping the display area twice will show your current progress. The FitBit Flex still supports use with the Android and iOS apps for more detailed feedback, but for users after just the basics, the FitBit Flex is the way to go.

FitBit Surge

The Surge is the most full-featured member of the FitBit family, outfitted with 8 separate sensors that track motion, speed, direction, GPS location, heart rate and other status indicators, storing a week’s worth of minute-by-minute activity data as well as daily totals for the past 30 days. It also functions as a caller ID when paired with a smartphone, and even shows text notifications along with allowing control of a compatible music player. Harvey Norman’s FitBit Surge release date is coming soon, so those looking for a top of the line model should definitely consider the Surge.

There’s a FitBit on the market for everyone, and the right one for you will depend on your individual lifestyle. Serious athletes and dedicated exercise enthusiasts will make the most of the features offered by a premium FitBit while those simply looking to track and add to their daily activities will be well-served by a more basic option.